Engine arrangement and method for heating exhaust after treatment equipment in an exhaust after treatment system

Abstract

An engine arrangement includes an engine ( 23 ), an exhaust line ( 25 ) connected downstream of the engine, exhaust after treatment equipment ( 27 ) in the exhaust line, a temperature sensor ( 29 a - 29 e ) for sensing a temperature of the exhaust after treatment equipment, and a turbo compound arrangement ( 37 ) including a turbo compound turbine ( 39 ) in the exhaust line. Exhaust flow through the turbo compound arrangement and the exhaust line is modified in response to one or more temperature sensor signals to increase heating of the exhaust after treatment equipment.

What is claimed is: 
     
       1. An engine arrangement, comprising:
 an engine; 
 an exhaust line connected downstream of the engine; 
 exhaust after treatment equipment in the exhaust line; 
 a temperature sensor for sensing a temperature of the exhaust after treatment equipment; and 
 a turbo compound arrangement including a turbo compound turbine in the exhaust line and means for modifying exhaust flow through the turbo compound arrangement and the exhaust line in response to one or more temperature sensor signals to achieve an exhaust temperature sufficient for regeneration of the exhaust after treatment equipment. 
 
     
     
       2. The engine arrangement as set forth in  claim 1 , wherein the modifying means modifies flow through the turbo compound arrangement by reducing flow through the turbo compound arrangement and the exhaust line in response to a temperature sensor signal that the temperature of the exhaust after treatment equipment is below a predetermined value to increase backpressure in the exhaust line upstream of the turbo compound turbine. 
     
     
       3. The engine arrangement as set forth in  claim 1 , wherein the modifying means modifies flow through the turbo compound arrangement by increasing flow through the turbo compound arrangement and the exhaust line in response to a temperature sensor signal that the temperature of the exhaust after treatment equipment is at or above a predetermined value to decrease backpressure in the exhaust line upstream of the turbo compound turbine. 
     
     
       4. The engine arrangement as set forth in  claim 1 , wherein the modifying means comprises a means for reducing rotational speed of the turbo compound turbine. 
     
     
       5. The engine arrangement as set forth in  claim 4 , wherein the turbo compound turbine is drivingly connected to a crankshaft of the engine, and the reducing means comprises a brake for braking rotation of the turbo compound turbine. 
     
     
       6. The engine arrangement as set forth in  claim 5  wherein the brake is arranged to apply sufficient resistance to movement of the turbo compound turbine to prevent energy from being returned to the crankshaft. 
     
     
       7. The engine arrangement as set forth in  claim 5 , wherein the brake is arranged to apply sufficient resistance to movement of the turbo compound turbine to increase a load on the engine. 
     
     
       8. The engine arrangement as set forth in  claim 1 , wherein the modifying means comprises a bypass conduit connected to the exhaust line upstream of the turbo compound turbine and a bypass valve movable from an open position in which flow to the turbo compound turbine is unrestricted and the bypass conduit is closed to a bypass position in which flow through the turbo compound turbine is restricted and the bypass conduit is opened. 
     
     
       9. The engine arrangement as set forth in  claim 8 , wherein, when the bypass valve is in the bypass position, flow through the turbo compound turbine and the bypass conduit together is less than flow through the turbo compound turbine when the bypass valve is in the open position. 
     
     
       10. The engine arrangement as set forth in  claim 1 , wherein the modifying means comprises means for reversing a direction of rotation of the turbo compound turbine. 
     
     
       11. The engine arrangement as set forth in  claim 10 , wherein the reversing means comprises a power transmission arrangement connecting the turbo compound turbine to a crankshaft of the engine, the power transmission arrangement being shiftable between a forward drive condition in which the turbo compound turbine is driven in a forward direction by gas flowing through the turbo compound turbine, a reverse drive condition in which the turbo compound turbine is driven in a direction opposite the forward direction by the crankshaft through the power transmission arrangement, and a neutral drive condition in which the crankshaft and the turbo compound turbine are disengaged. 
     
     
       12. The engine arrangement as set forth in  claim 10 , wherein the reversing means comprises a motor separate from the engine for driving the turbo compound turbine in a reverse direction when the power transmission arrangement is shifted to the one of the reverse drive condition and the neutral drive condition. 
     
     
       13. The engine arrangement as set forth in  claim 12 , wherein the motor is adapted to drive the turbo compound turbine in a forward direction. 
     
     
       14. The engine arrangement as set forth in  claim 1 , wherein the modifying means comprises a power transmission arrangement connecting the turbo compound turbine to a crankshaft of the engine, the power transmission arrangement being shiftable between a forward drive condition in which the turbo compound turbine is driven in a forward direction by gas flowing through the turbo compound turbine and at least one of a reverse drive condition in which the turbo compound turbine is driven in a direction opposite the forward direction, and a neutral drive condition in which the crankshaft and the turbo compound turbine are disengaged. 
     
     
       15. The engine arrangement as set forth in  claim 14 , wherein the modifying means comprises a motor separate from the engine for driving the turbo compound turbine in a reverse direction when the power transmission arrangement is shifted to the one of the reverse drive condition and the neutral drive condition. 
     
     
       16. A method for heating exhaust after treatment equipment in an exhaust after treatment system (EATS) for an engine, comprising:
 exhausting gas from the engine into an exhaust line downstream of the engine, the exhaust line including the exhaust after treatment system including the exhaust after treatment equipment, the exhaust line further including a turbo compound arrangement including a turbo compound turbine; 
 sensing temperature of the exhaust after treatment equipment; and 
 modifying exhaust gas flow through the turbo compound arrangement in response to one or more temperature sensor signals to achieve an exhaust temperature sufficient for regeneration of the exhaust after treatment equipment. 
 
     
     
       17. The method as set forth in  claim 16 , comprising modifying exhaust gas flow through the turbo compound arrangement by reducing rotational speed of the turbo compound turbine. 
     
     
       18. The method as set forth in  claim 16 , wherein the turbo compound turbine is drivingly connected to a crankshaft of the engine, the method comprising modifying exhaust gas flow through the turbo compound arrangement by braking rotation of the turbo compound turbine. 
     
     
       19. The method as set forth in  claim 16 , comprising applying, via the brake, sufficient resistance to movement of the turbo compound turbine to prevent energy from being returned to the engine. 
     
     
       20. The method as set forth in  claim 16 , comprising applying, via the brake, sufficient resistance to movement of the turbo compound turbine to increase a load on the engine. 
     
     
       21. The method as set forth in  claim 16 , comprising modifying exhaust gas flow through the turbo compound arrangement by reducing flow through the turbo compound arrangement and the exhaust line in response to a temperature sensor signal that the temperature of the exhaust after treatment equipment is below a predetermined value to increase backpressure in the exhaust line upstream of the turbo compound turbine. 
     
     
       22. The method as set forth in  claim 16 , comprising modifying exhaust gas flow through the turbo compound arrangement by increasing flow through the turbo compound arrangement and the exhaust line in response to a temperature sensor signal that the temperature of the exhaust after treatment equipment is at or above a predetermined value to decrease backpressure in the exhaust line upstream of the turbo compound turbine. 
     
     
       23. The method as set forth in  claim 16 , wherein the turbo compound arrangement comprises a bypass conduit connected to the exhaust line upstream of the turbo compound turbine and a bypass valve movable from an open position in which flow to the turbo compound turbine is unrestricted and the bypass conduit is closed to a bypass position in which flow through the turbo compound turbine is restricted and the bypass conduit is opened, the method comprising restricting flow through the turbo compound arrangement by moving the bypass valve to the bypass position. 
     
     
       24. The method as set forth in  claim 16 , comprising modifying exhaust gas flow through the turbo compound arrangement by reversing a direction of rotation of the turbo compound turbine. 
     
     
       25. The method as set forth in  claim 24 , comprising reversing the direction of rotation of the turbo compound turbine by turning the turbo compound turbine with a motor separate from the engine for driving the turbo compound turbine in a reverse direction. 
     
     
       26. The method as set forth in  claim 25 , comprising, after driving the turbo compound turbine in the reverse direction with the motor, driving the turbo compound turbine in a forward direction with the motor. 
     
     
       27. The method as set forth in  claim 25 , wherein a power transmission arrangement connecting the turbo compound turbine to a crankshaft of the engine is provided, the method comprising reversing the direction of rotation of the turbo compound turbine by shifting the power transmission arrangement from a forward drive condition in which the turbo compound turbine is driven in a forward direction by gas flowing through the turbo compound turbine and a neutral drive condition in which the crankshaft and the turbo compound turbine are disengaged and the motor drives the turbo compound turbine in the reverse direction.